Lean spike??

morganson

New Member
Jan 19, 2012
274
0
0
Columbia, SC
I have a question. I have a apexi afr monitor and after changing my o2 sensor i now get a stable reading. 10 at idle ect.
This ks where i become concerned. At cruise if i chop the throttle it spikes to 20 and may stay there until i tap the gas or may come right down.

Is this spike normal?

It does this on either the stock maf or the maft.
 

1James

Lurker
Mar 19, 2009
59
1
8
Bay Area, CA
By chop, do you mean close the throttle abruptly?

If so, then that is normal. If your engine speed is higher than idle and you have let off the throttle to cruise in gear, the ECU will turn the injectors off. Step on the clutch and watch your wideband return to normal idle AFR as your RPMs drop down to idle.

Hope this helps.
 

supranewbie

Member
Mar 23, 2011
377
0
16
46°47.0'N 120°09.0'W
Cylinder wash... It shouldn't go that rich until you're spooled up. What do you have for mods? Do you trust your reading? If it's really idling that rich I can't imagine it idling for very long. What do your plugs look like?